Yusuke Nakauchi M.D., Ph.D.

Postdoctoral Research Fellow, Stanford Cancer Center

Bio

My research projects aim to investigate the biology of human leukemia. I believe my research will contribute to clarify the disease pathogenesis of leukemia and help identify the critical cells to target to both prevent the development of de novo leukemia and halt relapse.

Honors & Awards

Stanford University School of Medicine, the Dean's Postdoctoral Fellowship, Stanford University (2016)

Overseas Award, Nakayama Foundation for Human Science (2014)

Boards, Advisory Committees, Professional Organizations

Associate Member, The American Association for Cancer Research (2015 - Present)

Additional Info

Links

Current Research and Scholarly Interests

From 2005 to 2010, my work as a clinical hematology fellow allowed me to experience first-hand how scientific advances that started in a laboratory can transform the lives of patients. While many of my patients were cured of their disease with allogeneic hematopoietic stem cell transplantation, underscoring the importance of anti-tumor immunotherapy in eradicating leukemia, I witnessed face-to-face their suffering from the long-term consequence of graft-versus-host disease (GVHD). This experience was ultimately what drove me to engage in research to discover novel therapies. For this reason, I embarked on a PhD program in 2010 to design antibody therapy to (i) target GVHD and (ii) target hematological malignancies. Under the mentorship of Professor Hiromitsu Nakauchi at the University of Tokyo, an international leader in hematopoiesis, I developed allele-specific anti-human leukocyte antigen (HLA) monoclonal antibodies for severe GVHD caused by HLA-mismatched hematopoietic stem cell transplantation (Nakauchi et al., Exp Hematol, 2015). This study was the first to find that anti-HLA antibodies can be used therapeutically against GVHD. That success gave me the motivation and confidence to further my research beyond targeting GVHD, to targeting leukemic stem cells through my current postdoctoral fellowship in the laboratory of Professor Ravindra Majeti, Department of Hematology at Stanford University.

Many people suffer from leukemia each year, but we still don’t know how to completely cure it. Recent advances in sequencing technologies have tremendously improved our understanding of the underlying mutations that drive hematologic malignancies, although, the reality is that the majority of the mutations are not easily “druggable” and the discovery of these mutations has not yet made a significant impact in patient outcomes. I view this perhaps the most crucial challenges facing a translational cancer researcher like myself. My current research is a major step toward my long term goal to make personalized medicine a reality for patients with acute myeloid leukemia (AML) and other hematologic malignancies. Although my research is focused on targeting Ten-Eleven Translocation methylcytosine dioxygenase-2 (TET2) mutations, I anticipate it will lead to a better understanding of the cell context requirement for TET2 mutations in AML and help identify the critical cells to target to both prevent the development of de novo leukemia and halt relapse. It may also prove of value to understanding of the biology of a range of other cancers.

Abstract

Graft-versus-host disease (GVHD), mediated by donor-derived alloreactive T cells, is a major cause of non-relapse mortality in allogeneic hematopoietic stem-cell transplantation (allo-HSCT). Its therapy is not well-defined. We established allele-specific anti-HLA monoclonal antibodies (ASHmAbs) that specifically target HLA molecules, with steady death of target-expressing cells. One such ASHmAb, against HLA-A*02:01 (A2-kASHmAb), was examined in a xenogeneic GVHD mouse model. To induce fatal GVHD, non-irradiated NOD/Shi-scid/IL-2Rγ(null) (NOG) mice were injected with healthy-donor human peripheral blood mononuclear cells (PBMCs), some expressing HLA-A*02:01, some not. Administration of A2-kASHmAb promoted the survival of mice injected with HLA-A*02:01-expressing PBMCs (p<0.0001) and, in humanized NOG mice, immediately cleared HLA-A*02:01-expressing human blood cells from mouse peripheral blood. Human PBMCs were again detectable in mouse blood 2-4 weeks after A2-kASHmAb administration, suggesting that kASHmAb may be safely administered to GVHD patients without permanently ablating the graft. This approach, different from those of existing GVHD pharmacotherapy, may open a new door for treatment of GVHD in HLA-mismatched allo-HSCT.

Abstract

To develop a new therapeutic monoclonal Antibody (mAb) for Hodgkin lymphoma (HL), we immunized a BALB/c mouse with live HL cell lines, alternating between two HL cell lines. After hybridization, we screened the hybridoma clones by assessing direct cytotoxicity against a HL cell line not used for immunization. We developed this strategy for establishing mAb to reduce the risk of obtaining clonotypic mAb specific for single HL cell line. A newly established mouse anti-human mAb (4713) triggered cytoskeleton-dependent, but complement- and caspase-independent, cell death in HL cell lines, Burkitt lymphoma cell lines, and advanced adult T-cell leukemia cell lines. Intravenous injection of mAb 4713 in tumor-bearing SCID mice improved survival significantly. mAb 4713 was revealed to be a mouse anti-human pan-HLA class II mAb. Treatment with this mAb induced the formation of large pores on the surface of target lymphoma cells within 30 min. This finding suggests that the cell death process induced by this anti-pan HLA-class II mAb may involve the same death signals stimulated by a cytolytic anti-pan MHC class I mAb that also induces large pore formation. This multifaceted study supports the therapeutic potential of mAb 4713 for various forms of lymphoma.

Abstract

The discovery of induced pluripotent stem cells (iPSCs) has created promising new avenues for therapies in regenerative medicine. However, the tumorigenic potential of undifferentiated iPSCs is a major safety concern for clinical translation. To address this issue, we demonstrated the efficacy of suicide gene therapy by introducing inducible caspase-9 (iC9) into iPSCs. Activation of iC9 with a specific chemical inducer of dimerization (CID) initiates a caspase cascade that eliminates iPSCs and tumors originated from iPSCs. We introduced this iC9/CID safeguard system into a previously reported iPSC-derived, rejuvenated cytotoxic T lymphocyte (rejCTL) therapy model and confirmed that we can generate rejCTLs from iPSCs expressing high levels of iC9 without disturbing antigen-specific killing activity. iC9-expressing rejCTLs exert antitumor effects in vivo. The system efficiently and safely induces apoptosis in these rejCTLs. These results unite to suggest that the iC9/CID safeguard system is a promising tool for future iPSC-mediated approaches to clinical therapy.

Abstract

Intraocular lymphoma (IOL) is rare lymphoma that frequently infiltrates the central nervous system (CNS). An optimal treatment has not been established, and its prognosis is quite poor. We treated three IOL patients with CNS involvement by concurrent administration of intravenous and intravitreal methotrexate (MTX) injection. The intraocular lesion responded in all patients. One patient achieved complete response (CR), whereas the other 2 patients were in partial response for CNS lesion, added whole brain radiation and achieved CR. In 3 eyes of 2 patients, an intravitreal MTX injection (vMTX) was administered 2 h after a systemic MTX injection (sMTX) and the intravitreal MTX concentration was measured twice: 2 h after sMTX and 24 h after vMTX. The half-life of MTX in the vitreous fluid was estimated to be 12.4-21.5 h by assuming the first-order elimination kinetics. Although the concentration was still high 24 h after vMTX (69.94-82.89 muM), there were no ocular complications. The serum MTX concentration was not influenced by adding vMTX to sMTX. Grade 3 adverse event, leukocytopenia, was observed in only 1 patient. No grade 4 event was observed. Although further evaluation is required, concurrent sMTX and vMTX may be effective for IOL with CNS involvement.